NON-ISOLATED HIGH EFFICIENCY BUCK CONSTANT CURRENT LED DRIVER

DESCRIPTION

UL9024 is a high precision LED constant current control chip

operating at critical conduction mode (CRM) with zero current

switched-on and peak current switched-off. It’s mainly targeted for

85Vac~265Vac universal mains and non-isolated buck LED power

systems.

UL9024 integrates proprietary high voltage supply circuit, which

eliminates VCC capacitor and startup resistor. The IC also combines

a high power MOSFET. Very simple application circuit is achieved.

UL9024 adopts critical conduction mode, which can turns on the

internal power MOSFET when the inductance current reaches zero,

reducing the power MOSFET switching loss, and achieving high

efficiency. With critical conduction mode, UL9024 outputs high

accuracy LED current, and further achieves excellent line regulation

and load regulation. It’s insensitive to inductance and the I-shape

inductance can be used.

UL9024 provides various protection features to enhance the

system reliability, including over current protection (OCP), short

circuit protection (SCP), and thermal adjustment, etc.

FEATURES

* No VCC capacitor and start-up resistor

* Wide input voltage range

* High efficiency (up to 95%)

* Highly accurate constant LED current

* Cycle-by-cycle current limitation

* LED short circuit protection

* Leading edge blanking control

* Under-voltage Lockout protection (UVLO)

* Thermal adjustment